Welcome!
Nano-scale transistors fill warehouse-scale supercomputers, yet their performance still constrains development of the jets that defend us, the medical therapies our lives depend upon, and the energy sources that will power our generation into the next.
We’re the Computational Physics Group at Georgia Tech. We develop computational models and numerical methods for these applications. Our methods buttress algorithms crafted for efficient use of the latest supercomputers and their architectures. We develop open-source software for these methods that scales to the world’s largest supercomputers.
In August 2025 our group conducted the largest-ever CFD simulation at 200T grid points (1 quadrillion degrees of freedom) on OLCF Frontier and LLNL El Capitan without loss of accuracy. This work is a 2025 Gordon Bell Prize finalist.
Check out our papers to learn more.
Openings? Visit this page if you’re interested in joining our group.
Examples of our work
Multiphase flow problems at the core of biological, energy, naval, and aerodynamic problems. We developed an implementation of the IGR technique with Florian Schäfer for simulating these flows. In August 2025 we set the record for the largest CFD simulation at 1 quadrillion degrees of freedom (200T grid points) for simulating these phenomena, using the entire OLCF Frontier system. MFC, an open-source solver we maintain, demonstrates such scale-resolving simulation of a multi-rocket-booster configuration above (viz. via Ph.D. student Ben Wilfong).
The spectral boundary integral method leads to high-fidelity prediction and analysis of blood cells transitioning to chaos in a microfluidic device. This method of simulation provides resolution of strong cell membrane deformation with scant computational resources. We developed a stochastic model for the cell-scale flow, enabling microfluidic device design and improving treatment outcomes. The video above shows a microaneurysm (viz. via student Suzan Manasreh).
News
September 17, 2025 Ph.D. students Ben Wilfong and Anand Radhakrishnan, along with group undergrad Tanush Prathi, lead work accepted to the SC25 workshop HPCTESTS. The workshop focuses on state-of-the-art HPC system testing methodologies, tools, benchmarks, procedures, and best practices. We use MFC to conduct these tests and pull out compiler bugs, performance regressions, and even repeatable driver failures on new flagship systems.
September 15, 2025 Spencer is at the UCAH Forum in Alexandria, Virginia this week. Say hi if you’re around!
September 4, 2025
The group is part of two DOE PSAAP IV centers! Official announcement here.
One is a ‘large’ predictive science center called the Center for Multiscale Modeling of Multiphase Combustion directed by S. Balachandar (UFlorida). Our group heads the HPC and CFD efforts.
The other is a slightly ‘smaller’ focused investigatory center (FIC), co-directed by Florian Schäfer at the Courant Institute and Brendan Keith at Brown. It is called CIGMO (Center for Information Geometric Mechanics and Optimization), where GT focuses on information-based regularization of computational hydrodynamics (Bryngelson institutional PI, along with Qi Tang (CSE) and Molei Tao (Math)).
26 August, 2025 New Ph.D. student Mark Zhang joins the grouop (UCLA undergrad.). Undergraduates Tanush Prathi and Mohammed Al-Mahrouqi join us as well, who were part of the team as undergraduate interns over the summer!
6 August, 2025
Spencer gives an invited user talk at the annual Oak Ridge Leadership Computing (OLCF) User Meeting. The topic was the combination of information geometric regularization, closely coupled compute optimizations, and networking via tight CPU-GPU interconnects for record-setting CFD simulations.
Also, Ph.D. student Ben Wilfong and Spencer win the data visualization showcase with with this animation of our simulation of Mach 10 rocket boosetrs!
Also, Spencer is elected to the OLCF User Group Executive Board.
5 August, 2025 Spencer is working with DOE lab collaborators as a Visiting Professor at PNNL on a potential quantum advantage for simulating CFD problems. Ph.D. student Zhixin Song spent the summer collaborating with PNNL on this front as well!
2 August, 2025 Our group is funded to continue working with Sandia National Lab and Ryan McMullen to work on multiphase bubbly flows and their hydrodynamic instabilities under extreme conditions.
30 July, 2025 Our work on parsimonious IMR (pIMR) has now appeared in Soft Matter! It describes and demonstrates a scheme for high-fidelity material inference that reduces the cost of experimentation or simulation by two orders of magnitude. With this, we enable material characterization in tractable time. In collaboration with Michigan, Brown, and UT Austin.
29 July, 2025 Florian Schäfer and I are presenting our collaborative work on computational fluid dynamics via IGR in back-to-back talks at the joint SIAM/CAIMS Annual Meeting tomorrow in Montreal, Wed July 30. Link Here.
24 July, 2025 Our group, in collaboration with Florian Schäfer, was featured in Oak Ridge News for our record-setting compressible shock-laden CFD simulations. They exceeded 100 trillion grid points while maintaining speed and accuracy via mixed-precision, unified memory addressing on the CPU-GPU interconnect, and information geometric regularization. These simulations targeted multi-rocket-engine outflow at Mach 15. These conditions and the geometry are similar to the SpaceX Starship superheavy 33-rocket booster.
